Detailed explanation of range usage in Go language: Master the basic syntax and apply it easily

Go language is a modern programming language that is favored by more and more developers due to its simplicity, efficiency and ease of learning. In the Go language, range is a very commonly used keyword, used to iterate arrays, slices, maps, channels and other data structures. This article will start with basic syntax, analyze the various uses of range in detail, and help readers better understand and apply this keyword through specific code examples.

1. Basic usage of range

In Go language, range is used to iterate arrays, slices, maps, channels and other data structures. Its basic syntax is:

for index, value := range data_structure {
    // 循环体
}

Among them, index represents the subscript (index) of the current element, value represents the value of the current element, data_structure represents the data structure to be iterated.

1.1 Iterating arrays or slices

numbers := []int{1, 2, 3, 4, 5}

for index, value := range numbers {
    fmt.Printf("索引为 %d 的元素是 %d
", index, value)
}

1.2 Iterating mapping

ages := map[string]int{"Alice": 23, "Bob": 25, "Cathy": 22}

for name, age := range ages {
    fmt.Printf("%s 的年龄是 %d 岁
", name, age)
}

1.3 Iterating channels

ch := make(chan int)

go func() {
    ch <- 1
    ch <- 2
    close(ch)
}()

for value := range ch {
    fmt.Printf("通道的值为 %d
", value)
}

2. Range expansion usage

Except In addition to the basic usage, range also has some extended usage to facilitate more flexible operations on data structures.

2.1 Only values ​​are required

numbers := []int{1, 2, 3, 4, 5}

for _, value := range numbers {
    fmt.Printf("元素值为 %d
", value)
}

2.2 Only indexes are required

numbers := []int{1, 2, 3, 4, 5}

for index, _ := range numbers {
    fmt.Printf("元素索引为 %d
", index)
}

2.3 range is used for strings

message := "Hello, 世界"

for index, char := range message {
    fmt.Printf("字符 %c 的索引为 %d
", char, index)
}

2.4 range is used for multi-dimensional arrays

matrix := [][]int{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}

for i, row := range matrix {
    for j, cell := range row {
        fmt.Printf("第 %d 行，第 %d 列的值为 %d
", i, j, cell)
    }
}

3. Summary

This article introduces in detail the basic usage and extended usage of the range keyword in the Go language, and demonstrates how to flexibly apply it through specific code examplesrangePerform iterative operations on the data structure. Readers can become more proficient in the use of range through practical exercises and improve programming efficiency. I hope this article can help readers better understand and use the range keyword, and further learn and apply the Go language.

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